SOUTH INDIAN: 27S is getting absorbed by larger and intensifying 26S(SEROJA). Invests 91S and 92P under monitoring,08/09utc update


08/09UTC. 9H LOOP. FROM LEFT TO RIGHT: INVEST 91S. TC 27S. TC 26S(SEROJA) AND INVEST 92P. IF NEEDED CLICK TO ANIMATE.


2021 APR 08 09UTC #SOUTHERNHEMISPHERE #SOUTHINDIANOCEAN
TC #26S #SEROJA  #WESTERNAUSTRALIA
WARNING 16
As of 06:00 UTC Apr 08, 2021:
Location: 17.0°S 111.7°E
Maximum Winds: 55 kt ( 100km/h)
Gusts: 70 kt ( 130km/h)
Minimum Central Pressure: 987 mb
INTENSIFYING
26S(SEROJA) LOCATED AT 08/06UTC APPROXIMATELY 640 KM NORTH-NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHWESTWARD AT 17 KM/H OVER THE PAST SIX HOURS.
Satellite bulletins are to be found in the comments of this post on JTWC BIS
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TC 27S  #SOUTHINDIANOCEAN #WESTERNAUSTRALIA
WARNING 14
As of 06:00 UTC Apr 08, 2021:
Location: 15.6°S 105.6°E
Maximum Winds: 35 kt ( 65km/h)
Gusts: 45 kt ( 85km/h)
Minimum Central Pressure: 999 mb
WEAKENING
27S LOCATED AT 08/06UTC APPROXIMATELY
Satellite bulletins are to be found in the comments of this post on JTWC BIS
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INVEST 91S  #SOUTHINDIANOCEAN #WESTERNAUSTRALIA
UPDATE
As of 06:00 UTC Apr 08, 2021:
Location: 9.6°S 93.4°E
Maximum Winds: 25 kt
Gusts: 35 kt ( 65km/h)
Minimum Central Pressure: 1004 mb
CURRENT POTENTIAL FOR THE NEXT 24HOURS: LOW.
Satellite bulletins are to be found in the comments of this post on JTWC BIS
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NVEST 92P  #SOUTHPACIFIC #CORALSEA
UPDATE
As of 00:00 UTC Apr 08, 2021:
Location: 12.6°S 154.4°E
Maximum Winds: 20 kt
Minimum Central Pressure: 1004 mb
CURRENT POTENTIAL FOR THE NEXT 24HOURS: LOW.

Cheers,
Patrick Hoareau
M974World
ILES SOEURS
Cyclone Class 4
 Cheers,PH.

Joint Typhoon Warning Center

26S(SEROJA). WARNING 16 ISSUED AT 08/09UTC. ANALYSIS INDICATES A MARGINALLY FAVORABLE ENVIRONMENT WITH VERY WARM  (30-31C) SEA SURFACE TEMPERATURE (SST) AND FAIR EASTERLY OUTFLOW  ALOFT SLIGHTLY OFFSET BY 15-20KTS OF EASTERLY VERTICAL WIND SHEAR.  TC 26S IS EXPECTED TO TRACK MORE SOUTHWESTWARD ALONG THE NORTHWEST  PERIPHERY OF THE DEEP-LAYERED SUBTROPICAL RIDGE (STR) ANCHORED OVER  WESTERN AUSTRALIA. AFTER 12H AND UP TO 24H, THE CYCLONE MAY  UNDERGO A SLIGHT PULL TO THE RIGHT WITH MINOR WOBBLING AS A RESULT  OF BINARY INTERACTION WITH TC 27S THAT WILL APPROACH TC 26S WITHIN  425KM. AFTER 36H, A MID-LATITUDE SHORTWAVE TROUGH APPROACHING  FROM THE SOUTHWEST WILL WEAKEN THE STR CAUSING THE TC TO BEGIN  ROUNDING THE STR AXIS AND TO TRACK MORE SOUTHWARD BEFORE  ACCELERATING SOUTHEASTWARD TOWARD THE GREAT AUSTRALIAN BIGHT. THE  AFOREMENTIONED FAVORABLE CONDITIONS WILL FUEL RAPID INTENSIFICATION  TO A PEAK OF 105KNOTS/US CAT 3 BY 48H. AFTERWARD, THERE WILL BE AN INCREASE  IN VERTICAL WIND SHEAR, COOLING SST, AND LANDFALL INTERACTION INTO SOUTHWEST  AUSTRALIA BETWEEN 72 AND 96H. ONCE OVER LAND, THE SYSTEM WILL  RAPIDLY ERODE THE SYSTEM DOWN TO 40KNOTS BY 96H AND UNDERGO EXTRA- TROPICAL TRANSITION. BY 120H, THE SYSTEM WILL HAVE COMPLETELY  BECOME A COLD-CORE GALE-FORCE LOW AS IT EXITS INTO THE AUSTRALIAN  BIGHT.
26S(SEROJA). WARNING 16 ISSUED AT 08/09UTC. ANALYSIS INDICATES A MARGINALLY FAVORABLE ENVIRONMENT WITH VERY WARM (30-31C) SEA SURFACE TEMPERATURE (SST) AND FAIR EASTERLY OUTFLOW ALOFT SLIGHTLY OFFSET BY 15-20KTS OF EASTERLY VERTICAL WIND SHEAR. TC 26S IS EXPECTED TO TRACK MORE SOUTHWESTWARD ALONG THE NORTHWEST PERIPHERY OF THE DEEP-LAYERED SUBTROPICAL RIDGE (STR) ANCHORED OVER WESTERN AUSTRALIA. AFTER 12H AND UP TO 24H, THE CYCLONE MAY UNDERGO A SLIGHT PULL TO THE RIGHT WITH MINOR WOBBLING AS A RESULT OF BINARY INTERACTION WITH TC 27S THAT WILL APPROACH TC 26S WITHIN 425KM. AFTER 36H, A MID-LATITUDE SHORTWAVE TROUGH APPROACHING FROM THE SOUTHWEST WILL WEAKEN THE STR CAUSING THE TC TO BEGIN ROUNDING THE STR AXIS AND TO TRACK MORE SOUTHWARD BEFORE ACCELERATING SOUTHEASTWARD TOWARD THE GREAT AUSTRALIAN BIGHT. THE AFOREMENTIONED FAVORABLE CONDITIONS WILL FUEL RAPID INTENSIFICATION TO A PEAK OF 105KNOTS/US CAT 3 BY 48H. AFTERWARD, THERE WILL BE AN INCREASE IN VERTICAL WIND SHEAR, COOLING SST, AND LANDFALL INTERACTION INTO SOUTHWEST AUSTRALIA BETWEEN 72 AND 96H. ONCE OVER LAND, THE SYSTEM WILL RAPIDLY ERODE THE SYSTEM DOWN TO 40KNOTS BY 96H AND UNDERGO EXTRA- TROPICAL TRANSITION. BY 120H, THE SYSTEM WILL HAVE COMPLETELY BECOME A COLD-CORE GALE-FORCE LOW AS IT EXITS INTO THE AUSTRALIAN BIGHT.

26S(SEROJA). NUMERICAL MODELS ARE IN FAIR AGREEMENT THROUGH 24H, WITH  NVGM AND AFUM BEING THE EXTREME LEFT OUTLIERS. NEAR 36/48H, THE  EXCESSIVE BINARY INTERACTION (EBI) WITH TC 27S, THE MODELS START  SPREADING APART SIGNIFICANTLY AS THE VORTEX BECOMES EMBEDDED IN THE  BAROCLINIC ZONE DURING EXTRA TROPICAL TRANSITION. OVERALL, THERE IS MODERATE CONFIDENCE IN  THE JTWC TRACK FORECAST THAT IS LAID SLIGHTLY RIGHT OF THE MODEL  CONSENSUS DURING THE MID-PORTION TO OFFSET THE EXTREME LEFT OUTLIERS  NVGM AND AFUM.
26S(SEROJA). NUMERICAL MODELS ARE IN FAIR AGREEMENT THROUGH 24H, WITH NVGM AND AFUM BEING THE EXTREME LEFT OUTLIERS. NEAR 36/48H, THE EXCESSIVE BINARY INTERACTION (EBI) WITH TC 27S, THE MODELS START SPREADING APART SIGNIFICANTLY AS THE VORTEX BECOMES EMBEDDED IN THE BAROCLINIC ZONE DURING EXTRA TROPICAL TRANSITION. OVERALL, THERE IS MODERATE CONFIDENCE IN THE JTWC TRACK FORECAST THAT IS LAID SLIGHTLY RIGHT OF THE MODEL CONSENSUS DURING THE MID-PORTION TO OFFSET THE EXTREME LEFT OUTLIERS NVGM AND AFUM.

26S(SEROJA). 08/0830UTC. ANIMATED MULTISPECTRAL  SATELLITE IMAGERY (MSI) SHOWS THAT THE SYSTEM HAS BEEN SHEARED ON  THE EASTERN SIDE PARTIALLY EXPOSING THE LOW LEVEL CIRCULATION (LLC).
26S(SEROJA). 08/0830UTC. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THAT THE SYSTEM HAS BEEN SHEARED ON THE EASTERN SIDE PARTIALLY EXPOSING THE LOW LEVEL CIRCULATION (LLC).

26S(SEROJA). 08/0602UTC. WELL-DEFINED LOW LEVEL CIRCULATION.
26S(SEROJA). 08/0602UTC. WELL-DEFINED LOW LEVEL CIRCULATION.

26S. WARNING 14 ISSUED AT 08/09UTC. ANALYSIS INDICATES THE CYCLONE IS IN A MARGINAL ENVIRONMENT WITH STRONG  SUBSIDENCE ALOFT ALONG THE EASTERN HALF DUE TO THE OUTFLOW FROM TC  26S AND MODERATE TO STRONG (20-25KT) EASTERLY VERTICAL WIND SHEAR  THAT ARE PARTLY OFFSET BY WARM (29C) SEA SURFACE TEMPERATURE. THE  SYSTEM IS IN A NEUTRAL AREA BETWEEN A LOW REFLECTION OF THE  SUBTROPICAL RIDGE TO THE SOUTHWEST, WEAK NEAR EQUATORIAL RIDGING TO  THE NORTHWEST, AND OUTFLOW PRESSURE FROM AN APPROACHING TC 26S,  CURRENTLY 650KM TO THE EAST. AS TC 26S GETS CLOSER, A BINARY  INTERACTION WILL COMMENCE DUE TO FUJIWARA EFFECT RESULTING IN TC 26S  TRACKING CYCLONICALLY INTO AN ARC NORTHEASTWARD. THE WARM WATER AND  INCREASED OUTFLOW WILL MARGINALLY OFFSET THE VWS AND PROMOTE A  MODEST INTENSIFICATION TO A PEAK OF 50KNOTS AS IT CRESTS THE ARC.  AFTERWARD, IT WILL RAPIDLY DECAY AS IT GETS RAPIDLY ABSORBED INTO  THE LARGER AND MUCH MORE DOMINANT TC 26S LEADING TO DISSIPATION BY  36H, POSSIBLY SOONER.
26S. WARNING 14 ISSUED AT 08/09UTC. ANALYSIS INDICATES THE CYCLONE IS IN A MARGINAL ENVIRONMENT WITH STRONG SUBSIDENCE ALOFT ALONG THE EASTERN HALF DUE TO THE OUTFLOW FROM TC 26S AND MODERATE TO STRONG (20-25KT) EASTERLY VERTICAL WIND SHEAR THAT ARE PARTLY OFFSET BY WARM (29C) SEA SURFACE TEMPERATURE. THE SYSTEM IS IN A NEUTRAL AREA BETWEEN A LOW REFLECTION OF THE SUBTROPICAL RIDGE TO THE SOUTHWEST, WEAK NEAR EQUATORIAL RIDGING TO THE NORTHWEST, AND OUTFLOW PRESSURE FROM AN APPROACHING TC 26S, CURRENTLY 650KM TO THE EAST. AS TC 26S GETS CLOSER, A BINARY INTERACTION WILL COMMENCE DUE TO FUJIWARA EFFECT RESULTING IN TC 26S TRACKING CYCLONICALLY INTO AN ARC NORTHEASTWARD. THE WARM WATER AND INCREASED OUTFLOW WILL MARGINALLY OFFSET THE VWS AND PROMOTE A MODEST INTENSIFICATION TO A PEAK OF 50KNOTS AS IT CRESTS THE ARC. AFTERWARD, IT WILL RAPIDLY DECAY AS IT GETS RAPIDLY ABSORBED INTO THE LARGER AND MUCH MORE DOMINANT TC 26S LEADING TO DISSIPATION BY 36H, POSSIBLY SOONER.


27S. THE NUMERICAL MODELS ARE IN FAIR AGREEMENT  WITH AFUM A SEVERE OUTLIER TO THE RIGHT AFTER 24H. ALL OTHER  MODELS ARE IN TIGHT AGREEMENT UNTIL 36H AS THE COMPLEX DYNAMICS  OF THE BINARY INTERACTION BEGINS, THERE IS LOW CONFIDENCE IN THE  JTWC TRACK FORECAST.
27S. THE NUMERICAL MODELS ARE IN FAIR AGREEMENT WITH AFUM A SEVERE OUTLIER TO THE RIGHT AFTER 24H. ALL OTHER MODELS ARE IN TIGHT AGREEMENT UNTIL 36H AS THE COMPLEX DYNAMICS OF THE BINARY INTERACTION BEGINS, THERE IS LOW CONFIDENCE IN THE JTWC TRACK FORECAST.

TC 27S. ANIMATED MULTISPECTRAL  SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM HAS MOSTLY MAINTAINED  CONVECTIVE SIGNATURE ON THE WESTERN SIDE AS TC 27S MOVED SLIGHTLY  NORTHWEST IN THE WEAK STEERING ENVIRONMENT. TC 26S(SEROJA) IS CURRENTLY  650KM TO THE EAST OF TC 26S.
TC 27S. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM HAS MOSTLY MAINTAINED CONVECTIVE SIGNATURE ON THE WESTERN SIDE AS TC 27S MOVED SLIGHTLY NORTHWEST IN THE WEAK STEERING ENVIRONMENT. TC 26S(SEROJA) IS CURRENTLY 650KM TO THE EAST OF TC 26S.

INVEST 91S. INVEST 91S IS IN A MARGINAL ENVIRONMENT FOR TROPICAL DEVELOPMENT  WITH GOOD POLEWARD OUTFLOW ALOFT AND WARM (29-30C) SEA SURFACE  TEMPERATURES OFFSET BY STRONG (25-30KTS) VERTICAL WIND SHEAR (VWS).  GLOBAL MODELS ARE IN GOOD AGREEMENT THAT INVEST 91S WILL CONSOLIDATE  AND INTENSIFY OVER THE NEXT 24-48 HOURS AS IT TRACKS TO THE  SOUTHEAST UNDER AN AREA OF WEAK (10-20KTS) VWS. MAXIMUM SUSTAINED  SURFACE WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL  PRESSURE IS ESTIMATED TO BE NEAR 1005 MB.
INVEST 91S. INVEST 91S IS IN A MARGINAL ENVIRONMENT FOR TROPICAL DEVELOPMENT WITH GOOD POLEWARD OUTFLOW ALOFT AND WARM (29-30C) SEA SURFACE TEMPERATURES OFFSET BY STRONG (25-30KTS) VERTICAL WIND SHEAR (VWS). GLOBAL MODELS ARE IN GOOD AGREEMENT THAT INVEST 91S WILL CONSOLIDATE AND INTENSIFY OVER THE NEXT 24-48 HOURS AS IT TRACKS TO THE SOUTHEAST UNDER AN AREA OF WEAK (10-20KTS) VWS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1005 MB.

INVEST 92P. INVEST 92P IS IN A FAVORABLE ENVIRONMENT FOR TROPICAL DEVELOPMENT WITH WARM (29-30C) SEA SURFACE  TEMPERATURES, LOW (5-10KTS) VERTICAL WIND SHEAR (VWS), AND EXCELLENT  POLEWARD OUTFLOW. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT INVEST  92P WILL CONSOLIDATE AS IT TRACKS TO THE SOUTHEAST, REMAINING  LARGELY ASYMMETRIC, POTENTIALLY REACHING WARNING THRESHOLD IN THE  NEXT SEVERAL DAYS.
INVEST 92P. INVEST 92P IS IN A FAVORABLE ENVIRONMENT FOR TROPICAL DEVELOPMENT WITH WARM (29-30C) SEA SURFACE TEMPERATURES, LOW (5-10KTS) VERTICAL WIND SHEAR (VWS), AND EXCELLENT POLEWARD OUTFLOW. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT INVEST 92P WILL CONSOLIDATE AS IT TRACKS TO THE SOUTHEAST, REMAINING LARGELY ASYMMETRIC, POTENTIALLY REACHING WARNING THRESHOLD IN THE NEXT SEVERAL DAYS.

08/06UTC. JTWC IS ISSUING 6HOURLY WARNINGS ON TC 26S(SEROJA) AND ON TC 27S. 3HOURLY SATELLITE BULLETINS ARE ISSUED FOR BOTH SYSTEMS.
08/06UTC. JTWC IS ISSUING 6HOURLY WARNINGS ON TC 26S(SEROJA) AND ON TC 27S. 3HOURLY SATELLITE BULLETINS ARE ISSUED FOR BOTH SYSTEMS.
Rédigé par PATRICK HOAREAU le Jeudi 8 Avril 2021 à 13:45